1. Field of the Invention
This invention relates to a sliding jack support and particularly to a jack support which supports the jack post of a trailer tongue and permits the trailer tongue to be shifted into alignment with the trailer hitch of a towing vehicle.
2. Description of the Related Art
For purposes of this description, the word "trailer" is meant to refer to any towed vehicle, whether the towed vehicle comprises one unit (e.g., a horse trailer or camper), or whether the trailer is a separate body from the load being supported by it (e.g., a boat on a trailer). Virtually every trailer has a jack post attached to its trailer tongue. On some trailers, the jack post mounts a pivotal wheel. In either case, the jack post is a vertical metal cylinder which is lowered to the ground by a jack and supports the front portion of the towed vehicle when the trailer is not attached to the towing vehicle, for example, when storing the trailer in a garage, or resting it at a campsite. Trailer owners devise a number of methods for providing a base for the jack post to allow it to rest on the ground without penetrating particularly soft ground. For example, trailer owners often rest the jack post on cinder blocks and wood planks. Commercially available metal cone-shaped stands are also used. When the jack post is equipped with a wheel, the wheel may be used to support the jack post on the ground surface, but in soft ground, the wheel is not a satisfactory means of support.
Typically a trailer hitch of the towing vehicle contains a ball, and the trailer tongue of the towed trailer has a socket which fits over the ball of the trailer hitch to attach the trailer to the towing vehicle. Particularly for large or heavily loaded trailers, it is very difficult to maneuver the towing vehicle or the trailer so that the ball and socket are precisely aligned and able to be coupled because it is very difficult to lift or shift the trailer tongue. It is also difficult for the driver of a towing vehicle to precisely align the trailer hitch of the towing vehicle with the trailer tongue of the trailer because the driver cannot see the ball and socket, and therefore cannot maneuver the towing vehicle to meet the trailer tongue. In response to this problem, many devices have been proposed.
Some trailer devices address the alignment problem by providing devices which enable the operator to move the trailer tongue to the ball on the trailer hitch once the towing vehicle has been positioned close to the trailer. However, when using these devices, the operator must physically move and bear the full weight of the trailer tongue in order to move the trailer tongue. For example, U.S. Pat. No. 4,431,208 of Geeves, describes a trailer walker having a handle positioned in a base holding a jack post. The operator must lift and swing the handle of Geeves in order to move the base, which ultimately moves the jack post of the trailer tongue. The operator must also be able to lift much of the tongue weight in order to use the device. Similarly, U.S. Pat. No. 3,084,953 of McGregor describes a trailer device having a positioning track which is placed under a jack wheel of a trailer and which is moved to define a path for moving the trailer. In order to use the positioning track of McGregor, the operator must push or pull the trailer tongue to cause the jack wheel to move in the track. U.S. Pat. No. 4,911,460 of DePaula, describes a device in which the trailer tongue is moved by the turning of a crank. Turning the crank rotates a horizontal lead screw which is engaged to a threaded float carriage located within the socket housing of the jack post to permit the movement of the socket along the lead screw when the crank is turned. The crank of DePaula is very near to the ground and difficult to turn, especially if the load on the trailer tongue is heavy. These devices are effective as alignment devices if the trailer tongue load is moderate. However, the tongue weight of trailers can vary anywhere from 100 pounds to 1000 pounds. For tongue weights of this magnitude, the described devices are generally ineffective.
Applicant's prior U.S. Pat. No. 5,009,444 represents a type of slideable jack stand in which the jack post is received in a socket which is mounted on a ground engaging support and which slides on a low friction surface. While the type of jack stand described in applicant's prior patent represents a significant advance in the art, it has been found to be useful primarily with trailers having a relatively low or medium tongue weight. The sliding jack support of the present invention while incorporating some of the features of the slideable jack stand of applicant's prior patent, seeks to provide a wider range of shifting, greater leverage for the operator to lessen the force required to shift the trailer tongue, and a more versatile locking arrangement enabling the jack post to be locked in any of number of shifted positions.
While other prior art might be cited, it is believed that the cited prior art is sufficient to illustrate the state of the art.
It is therefore an object of the invention to provide a sliding jack support serviceable as a trailer tongue alignment device and which is easy to use with both light and heavy weight tongue loads.
A further object of the invention is to provide a sliding jack support serviceable as a trailer tongue alignment device and which is operable over a relatively wide range without the operator having to exert tremendous force.
Another object of the invention is to provide a sliding jack support which may fix the tongue in any of several laterally shifted positions or in a central position or serve as a fixed jack post support for long term storage, camping or the like.
Other objects and advantages will be more fully apparent from the following disclosure and appended claims.